1. Technical Field
The present invention relates to a printing apparatus.
2. Related Art
As printing apparatuses, ink jet type printers which form images by ejecting ink onto a printing medium have been well known.
Among such ink jet type printers, there has been an ink jet type printer which performs printing using colored inks, such as CMY inks, and a colorless transparent ink (a clear ink).
JP-A-2002-307755 is an example of related art.
Here, a film type medium made of polystyrene, polypropylene or the like is sometimes used as a printing medium. Such a film type medium is likely to, inside a printer, cause electrostatic charges on its surface due to a friction with a paper-feeding roller made of a metallic material (an aluminum material, an iron material or the like). Further, an amount of the electrostatic charges is influenced by a state of the friction and thus varies depending on a position on the surface of the medium.
When an ink is ejected onto such a printing medium on which the variation of the amount of electrostatic charges is occurring, ink mists (so-called satellites) which arise in conjunction with the ink ejection are accumulated on regions in each of which the amount of electromagnetic charges is large. As a result, sometimes, haze-like image degradations occur on printed materials.
Meanwhile, it is possible to reduce the amounts of electrostatic charges to a substantially uniform amount by applying an ancillary ink, such as a clear ink, to the entire surface of a printing medium in advance.
Nevertheless, there is a problem that, when such a clear ink is applied to the surface of a printing medium, an image forming liquid (a colored ink) and the clear ink are mixed with each other, so that blurs occur on images.